VAT polymerization encompasses a group of 3D printing processes characterized by hardening photosensitive resins according to a pre-specified pattern with UV radiation. The 3D build plate begins submerged in a ‘vat’ of viscous photo-sensitive resin. The resin is then incrementally cured to develop a hard texture to form the desired object layer by layer. Typically, post processing includes further curing of the finished object in order to reinforce the chemical bonds and ensure the integrity of the print.

VAT polymerization encompasses a few different 3D printing methods including stereolithography (SLA), digital light processing (DLP), and masked stereolithography (MSLA) also known as LCD 3D printing.


Stereolithographic Apparatus – or more simply referred to as Stereolithography. SLA, or resin printing – is likely the most well known vat polymerization method. Ultraviolet light is directed – like a pen light – and used to cause chemical monomers to link together to form polymers that make up a form of a 3 dimensional object.

Stereolithography can be used to create prototypes for products in development, medical models, and computer hardware, as well as in many other applications. While stereolithography is fast and can produce almost any design, it can be expensive.

As mentioned, stereolithography works by focusing an ultraviolet (UV) laser on to a vat of photopolymer resin. Guided by CAD/CAM software and using mirror-like components called galvanometers, the UV laser ‘draws’ a pre-programmed pattern on to the surface of the photopolymer vat. Since photopolymers are sensitive to ultraviolet light, the resin is photochemically solidified to form a single layer of the desired 3D pattern. The build platform then adjusts and a movable blade recoats the top of the tank with resin, the laser ‘draws’ the next layer which bonds to the previous layer.  The process is repeated for each layer of the design until the 3D object is complete.

Completed parts must then be given a solvent bath to clean away excess and unused resin, and often times require further curing to ensure the integrity of the printed object and the characteristics of the material.


Like SLA, Digital Light Processing is also a form of resin printing but with some key differences.

DLP makes use of a specially designed Digital Light Projector Screen. The projector has the capacity to ‘flash’ (almost like a camera) an entire layer at a time, making the process much faster than SLA. Up until recently, the trade off between SLA and DLP has been speed for quality. Since the DLP is a digital technology, the 2D image that is projected is composed of pixels. When translated into three dimensions, they become voxels. Think of miniscule Lego blocks.

However advances in software and in the DLP technology generally have resulted in prints that are almost indistinguishable from SLA prints and thus presents manufacturers with a unique tool to add to their production process.


Soonser is at the forefront of industrial SLA printer technology, combining large vat size with numerous innovations such as the VarioBeam to enhance not only resolution but the overall production speed.

The Mars Pro 600/850/1600 line of printers is a robust, ergonomically and aesthetically attractive line of printers designed to offer users the optimal combination of ease of use, low maintenance, and high speed and precision.

precise and efficient

  • the patented variable beam technology makes use of a wide beam UV laser that varies the spot size to suit the resolution of the print.
    • in practical terms, the variable beam can increase print speed by up to 100% without sacrificing print quality
  • each printer incorporates a refined high precision resin level control with a +/- 0.01 tolerance, resulting in a better surface finish
  • each printer also incorporates a dense marble build platform to enhance build precision, durability, and ease of print removal

open source

  • any resin with a 355 nm rating can be used in the Mars Pro printers, representing a wide range of mechanical properties such as:
    • polypropylene-like and flexible – Somos 9120
    • ABS-like – Somos GP 14122 or Accura ABS Black
    • high temperature applications – Somos PerFORM
    • investment casting – Somos ELEMENT
    • …and more
  • The Mars Pro control software allows use of 3rd party .stl processing software like NETFABB and Materialize Magics
Mars Pro 600
Mars Pro 850
Mars Pro 1600


Vat polymerization makes use of viscous resins rather than filaments.

While the breadth of 3D printable resins is not as broad when compared to FDM filaments, it is growing with new resins being researched and developed to suit specific requirements. And once developed, they are able to achieve their goals with superior results. And when combined with increased speed and capacity of commercial grade vat polymerization methods like SLA, they provide an incredibly potent manufacturing tools.

EPLUS3D and DSM Somos achieved considerable success and acclaim in their resins, and we have shortlisted a number of them below.

Click on any of the pictures below for resin specific information.






Waterclear Ultra


i3D offers each of the resins shown. For more information, please visit our store.

Somos Taurus brings the combination of thermal and mechanical performance that until now was not possible with stereolithography materials. Its robustness combined with a charcoal grey appearance makes it ideal for the most demanding functional prototyping and even end-use applications.

Somos® Taurus is the latest addition to the high impact family of stereolithography (SLA) materials from DSM Additive Manufacturing. Parts printed with this material are easy to clean and finish. The higher heat deflection temperature of this material increases the number of applications for the part producer and user.

Key Benefits for 3D Printing

  • Superior strength and durability
  • Wide range of applications
  • Excellent surface and large part accuracy
  • Heat tolerance up to 90°C
  • Thermoplastic-like performance, look and feel


By using Somos® Taurus to print your parts, you get the added value of excellent surface quality and isotropy, enabling reduced job times for highly detailed parts with more uniform performance. The darker color of Somos® Taurus also gives an added richness to your parts to minimize part finishing and painting making it a great choice for the automotive and aerospace industries.

Zero-emission racing car gets Somos® Taurus’ air in-take ducts for cooling electric motors

Somos® Taurus helped the  Forze Hydrogen Electric Racing Project develop an essential part for the Forze hydro-electric fuel cell that’s light weight and heat resistant which makes it ideal for the latest generation of the car, Forze VIII. Read the full story clicking the link below.

Creating intricate, hollow composite parts has always been a challenge for the traditional manufacturing industry – but not for additive manufacturing. Somos® DMX-SL™ 100 is a durable and tough stereolithography (SL) material that enables you to produce complex, hollow composite parts in days thanks to a unique and cost-effective ‘dry removal’ process: and all with no compromise on quality and aesthetics.

Somos® DMX-SL™ 100 is a unique material for creating 3D printed sacrificial tooling for a wide range of applications, from automotive parts to consumer products to electronics and healthcare. It produces very accurate parts with a superb surface finish and outstanding feature detail.

Somos® DMX-SL™ 100 withstands the extreme temperatures of the autoclave process utilized in composites manufacturing, maintaining its flexural strength, elongation and tear resistance.

But where it really breaks the mold is in the speed, efficiency and design freedom it brings. It’s all based on a unique ‘dry removal’ process that enables mandrels to be removed from complex and convoluted geometries after the autoclave without the need for submersion in caustic (which can affect the composite part).

As a result, manufacturers have more design freedom to create high temperature, cost-effective tools in days rather than weeks or sometimes even months.

Key Benefits

  • Stereolithography accuracy
  • Extreme durability
  • Stiff & tough parts
  • Greater design freedom
  • High feature detail and smooth finish
  • Faster part design.


  • Automotive & Transportation: ducts, pipes and conduits, high-end automotive intake pipes, fluid-holding tanks, electric vehicle (EV) battery cooling solutions.
  • Consumer products: sports and leisure goods, luxury goods, interior design.
  • Electronics: bespoke light-weight enclosures, complex wiring looms, robotic components.
  • Healthcare: precision-molded internals for prosthetics.

Through continuous interaction with our customers, pattern makers and foundries, DSM Additive Manufacturing has developed Somos® Element as the next generation of stereolithography resins specifically designed for producing investment casting patterns.

Key Benefits for 3D Printing

  • Very clean burnout with low residual ash
  • Low viscosity
  • Dimensionally stable


Somos® Element is a new antimony-free stereolithography material that has been specifically created to improve the repeatability and quality of 3D printed casting patterns.

Patterns created with Somos® Element have strong green strength, are dimensionally stable during storage and leave a minimal amount of ash residue after burnout. Any residue that is left behind is easily removed, leaving a perfectly clean void in the ceramic mold. This translates into less mold prep and lower rates of rework saving customers time and money.

Somos® Momentum provides a compelling solution that combines rich feature detail and dimensional stability with the most efficient printing outcomes available without compromising on surface quality and dimensional accuracy.

Footwear manufacturers face a multitude of challenges, from developing durable solutions to managing design and the range of sizes required. They continue to seek more effective means to develop new designs to meet increasingly diverse customer needs, while also striving to quicken the pace of design and innovation. Additive manufacturing for footwear tooling has played a key role, and the inherent design flexibility, feature detail and surface quality offered by SL has led this technology into the mainstream. Footwear manufacturers continue to push for faster design iteration, shorter route to market and more cost- and time-efficient approaches.

DSM collaborated with key footwear manufacturers to develop an additive manufacturing material that addresses the specific needs for footwear tooling. Somos® Momentum offers high part accuracy, quality and fine feature detail. The outstanding accuracy of the resin allows the forming of sharp features which in turn enables the creation of detailed soles not only in initial design, but also translated into the aluminum mold.  In addition, the pink color of the material makes it easy to discern key features in the design and to inspect the parts for surface defects. Taking this technology a step further, direct printing of the sole will omit the need for detailing or texturing, speeding up the traditional tooling process up to 60%, enabling a cost reduction up to 30%.

Key Benefits

  • Highest efficiency stereolithography material
  • High accuracy and surface quality
  • Complex shapes and feature detail
  • Eliminates chemical texturing process
  • Color facilitates inspection of feature detail and quality
  • Overall cost saving during development and manufacturing

The need for movable parts is a constant when it comes to prototyping. Being able to ensure the proper fit for parts within a component can save both time and money. Whatever industry or application, the Somos® 9120 provides the ultimate solution for form, fit and function with parts that are semi-flexible.

Key Benefits

  • Translucent appearance
  • Superior chemical resistance
  • Strong memory retention

With mechanical properties that mimic many engineering plastics, parts created from Somos® 9120 exhibit superior fatigue properties, strong memory retention and a good balance of properties between rigidity and functionality.


Somos® 9120 offers superior chemical resistance and a wide processing latitude, ideal for automobile components, electrical housings and medical products.

Somos® WaterClear Ultra 10122 is a fast and easy to use optically clear SLA resin. It produces colorless, functional and accurate parts that simulate an acrylic appearance. Parts produced from Somos® WaterClear Ultra 10122 exhibit excellent water and temperature resistance.

Key benefits

  • Extraordinary optical clarity 
  • Superior moisture resistance 
  • Easy to use and finish


Somos® WaterClear Ultra 10122 is ideal for applications such as fluid flow analysis, master patterns, concept and functional models. This material also provides refractive values similar to engineered plastics for functional testing in optical light transmission work.



 SH8900-H is an ABS like SL resin which has accurate and durable features. It is designed for solid state SLA platforms. SH8900-H can be applied in master patterns, concept models, general parts and functional prototypes in the field of automotive, medical and consumer electronics industries.


  • Has medium viscosity for easier recoating, part and machine cleaning
  • Improved strength, heat and chemical resistance, lower hygroscopy
  • Minimal post processing and part finishing
  • Long storage life-span when in machine and not in-use.



  • Need less part finishing time, easier post-curing
  • Building accurate and high tough parts with an improved dimensional stability
  • High quality controls for vacuum casting parts
  • Low shrinkage
  • Vibrant white color, good resistance to yellowing

Outstanding machinable SLA material

Outstanding temperature resistant

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